Substituted phthalocyanine

ABSTRACT

A phthalocyanine compound of the formula: 
     
         (R--X--).sub.m Pc(--Y--R.sup.1 --Z--).sub.n (--SO.sub.3 M).sub.p I 
    
     wherein 
     Pc is a phthalocyanine nucleus (Pc); 
     each 
     R independently is a monovalent aromatic radical linked to a peripheral carbon atom of the Pc nucleus through X; 
     X selected from S, Se and Te; 
     m is 4 to 16; 
     each 
     R 1  independently is a divalent aromatic radical linked to two adjacent peripheral carbon atoms of the Pc nucleus through Y and Z; 
     Y is selected from S, NT, Se and Te; 
     Z is selected from S, Se, Te, NT and O; 
     T is selected from H, alkyl and aryl; 
     n is 0 to 7; 
     M is H, a metal or optionally-substituted ammonium; 
     and 
     P is from 1 to 16. 
     The compounds have a significant absorption band in the near infra red and depending on the number of sulphonic acids groups and the nature of the counter ion are soluble in aqueous and polar organic media. The compounds are useful in many applications where absorption of infra-red radiation is desirable, such as in OCR readable inks, rapid-drying inks, security printing and reprographic toners.

This specification describes an invention relating to certainsubstituted-thio-phthalocyanine sulphonates which absorb in the nearinfra-red region of the electromagnetic spectrum, e.g. at 700-1500nanometers (nm) and especially at 750-1100 nm.

According to the present invention there is provided a phthalocyaninecompound of the formula:

    (R--X--).sub.m Pc(--Y--R.sup.1 --Z--).sub.n (--SO.sub.3 M).sub.p (I)

wherein

Pc is a phthalocyanine nucleus (Pc);

each

R independently is a monovalent aromatic radical linked to a peripheralcarbon atom of the Pc nucleus through X;

X selected from S, Se and Te;

m is 4 to 16;

each

R¹ independently is a divalent aromatic radical linked to two adjacentperipheral carbon atoms of the Pc nucleus through Y and Z;

Y is selected from S, NT, Se and Te;

Z is selected from S, Se, Te, NT and O;

T is selected from H, alkyl and aryl;

n is 0 to 7;

M is H, a metal or optionally-substituted ammonium;

and

p is from 1 to 16.

The core of the phthalocyanine (Pc) nucleus may be metal-free or containany of the metals or oxymetals which are capable of being complexedwithin the core. Examples of suitable metals and oxymetals aremagnesium, palladium, gallanyl, vanadyl, germanium, indium and moreespecially copper, particularly copper(II), nickel, cobalt, iron, zinc,lead and cadmium. In this specification a metal-free phthalocyanine willbe designated, H₂ Pc, and a metallised phthalocyanine, such ascopper(II) phthalocyanine, will be designated, Cu(II)Pc.

Each R is preferably optionally substituted mono- or bi-cyclic aryl orheteroaryl, and is more preferably selected from phenyl, naphthyl,thienyl, furyl, pyrryl, thiazolyl, isothiazolyl, quinolyl, indolyl,pyridyl, benzoimidazolyl and benzothiazolyl, which may carry up to 3,but preferably not more than 2, substituents. Where R is phenyl thesubstituents may be situated in the ortho, meta and/or para positionswith respect to the X linking atom. Preferred substituents are selectedfrom C₁₋₂₀ -alkyl, especially C₁₋₄ alkyl; C₁₋₂₀ -alkoxy, especially C₁₋₄-alkoxy; S-C₁₋₂₀ -alkyl, especially S-C₁₋₄ alkyl; aryl, especiallyphenyl; S-aryl, especially S-phenyl; halogen, especially chloro orbromo; nitro; cyano; tertiary amino, such as di-N-alkyl-,N-alkyl-N-aryl- and di-N-aryl-amino, especially di-(C₁₋₄ -alkyl)amino,N-C₁₋₄ -alkyl-N-phenylamino and di-phenylamino; --COOH and acyl andacylamino, such as COT¹, CONT¹ T², SO₂ T¹ and SO₂ NT¹ T² in which T¹ andT² are each independently selected from H, alkyl, especially C₁₋₄ alkyl;aryl, especially phenyl and aralkyl, especially benzyl.

It is preferred that the average value of m is from 6 to 16 and moreespecially from 8 to 16.

Each R¹ is preferably phen-1,2-ylene or naphth-3,4-ylene orphen-1,2-ylene or naphth-3,4-ylene substituted by a group selected fromany of the substituents listed above for R. It is preferred that R¹ isunsubstituted or is substituted by halogen or C₁₋₁₀ -alkyl, and moreespecially C₁₋₄ -alkyl. It is also preferred that the average value of nis from 0 to 5.

It is preferred that X is S, also that Y is S or NT and also that Z is Sor NT. It is especially preferred that Y is S and Z is NT. It ispreferred that T is H, C₁₋₄ -alkyl, especially methyl, or phenyl.

It is preferred that 2n+m is from 13 to 16, and more preferably 14, 15or 16. The remaining peripheral carbon atoms on the phthalocyaninenucleus preferably carry H, halogen, especially chlorine or bromine, OH,alkoxy, preferably C₁₋₄ -alkoxy and more especially isoamyloxy, or acombination of these groups.

The sulphonate groups, --SO₃ M, are preferably located on the peripheralaromatic groups, R and R¹. Depending on the nature of the group M,aqueous solubility generally increases with the number of sulphonategroups and this can be modified by increasing or decreasing the extentof sulphonation to suit any specific application. For reasonablewater-solubility it is preferred that there are, on average, at least 3,and more preferably at least 5 sulphonate groups per molecule althoughthe compound may contain 10 or more sulphonate groups. Where relativelyhigh solubility is required it is desirable that the aromatic groups Rand R¹ have, in total, sufficient free and unhindered carbon atoms toaccommodate at least 5, more preferably at least 8, and especially from10 to 15, sulphonate groups.

For any particular number of sulphonate groups, solubility in highlypolar media, such as water and aqueous-based systems is enhanced if M isan alkali metal, unsubstituted ammonium or ammonium carrying hydrophilicsubstituents. Thus, in a preferred compound of Formula I for use inaqueous-based systems, M is an alkali metal, especially, sodium,potassium or lithium, or unsubstituted ammonium. The term aqueous-basedsystems includes media comprising a substantial proportion, preferablyat least 50% by weight, of water and optionally other water-miscibleliquids such as simple glycols, e.g. ethylene glycol, or lower aliphaticalcohols, e.g. methanol.

It has, however, been found that solubility in less polar media,comprising a minor proportion, preferably less than 25%, water orcomprising only polar, organic liquids, such as glycols, e.g. ethyleneglycol, diethylene glycol and poly(alkylene glycols) and alcohols. e.g.methanol, ethanol, propanol and butanol is enhanced when M issubstituted ammonium, carrying at least one fatty aliphatic group,especially C₁₋₂₀ -alkyl or C₁₋₂₀ alkenyl, or is arylguanidinium,especially diarylguanidinium, such as diphenylguanidinium anddi-2-tolylguanidinium.

The substituted ammonium group is preferably of the formula NQ₄ in whichat least one Q is a fatty aliphatic group or two Qs, together with the Natom, form an heteroalicyclic or heteroaromatic group, such as pyridino,piperidino or morpholino. It is further preferred that the other two orthree Qs, each independently represents H, C₁₋₄ -alkyl, phenyl orbenzyl. It is especially preferred that at least one, and morepreferably three, of the groups represented by Q is H.

The fatty aliphatic group represented by Q preferably contains from 6 to10, more preferably from 7 to 10, and especially preferably 8 or 9,carbon atoms. Preferred fatty aliphatic groups are alkyl and alkenyl andmore especially such groups in which the carbon chain contains at leastone branch and more especially from 2 to 4 branches. Preferred alkylgroups, represented by Q, containing 8 or 9 carbon atoms, are3,5,5-trimethylhexyl, 1,1,3,3-tetramethylbutyl and 2-ethylhexyl.Examples of other aliphatic chains are 1-ethyl-3-methylpentyl,1,5-dimethylhexyl, 1-methylheptyl, octyl, nonyl, 1,4-dimethylheptyl,1,2,2-trimethylpropyl, 2-ethylbutyl, 1-propylbutyl, 1,2-dimethylbutyl,2-methylpentyl, 1-ethylpentyl, 1,4-dimethylpentyl, hexyl, 1-methylhexyl,3-methylhexyl, heptyl, 1,3,3-trimethylbutyl, 1-methylnonyl, decyl,dodecyl, tridecyl, pentadecyl, hexadecyl and octadecyl. The substitutedammonium preferably carries one fatty alkyl group as described above theremaining groups being preferably H, C₁₋₄ -alkyl, especially, methyl, oraralkyl, especially, benzyl. It is, however, preferred that at leastone, and more preferably all three, of the remaining groups representedby Q is H. Suitable ammonium groups are 2-ethylhexylammonium,1,1,3,3-tetramethylbutylammonium, 3,5,5-trimethylhexylammonium,lauryltrimethylammonium, laurylbenzyldimethylammonium,octadecyltrimethylammonium and more especially cetylpyridinium andcetyltrimethylammonium.

The arylguanidinium group is preferably diarylguanidinium, of theformula:

    T.sup.3 --NH--C(NHT.sup.4)--NH--T.sup.3

in which each T³ independently represents an optionally substitutedphenyl group, especially phenyl or C₁₋₄ -alkylphenyl and T⁴ is H or C₁₋₄-alkyl. It is preferred that the two groups T³ are identical andexamples are phenyl and 2-tolyl.

In an especially preferred compound of Formula I,

Pc is Cu(II)Pc;

R is phenyl, C₁₋₄ -alkylphenyl or C₁₋₄ -alkoxyphenyl;

X is S; m is 8 to 16;

R¹ is phen-1,2-ylene, naphth-1,2-ylene or naphth-2,3-ylene;

Y is S; n is 0 to 4;

Z is NT, S or O T is H or C₁₋₄ -alkyl

M is selected from H, alkali metal (especially Na), NH₄, NH₃ Q¹ anddiarylguanidinium; and

Q¹ is as hereinbefore defined, especially C₈₋₉ -alkyl having from 1 to 4branches.

The compounds of Formulae I and II may be prepared by directsulphonation of a compound of Formula I in which p=0. The conditions forsulphonation depend on the number of sulphonate groups which it isdesired to introduce into the molecule. However, it is possible tointroduce up to 15 or 16 sulphonate groups by the use of 100% sulphuricacid at ambient temperatures. Compounds of Formula I in which p=0 andtheir preparation are described in EP 155780A.

The present compounds have a significant absorption band in the nearinfra-red region of the electromagnetic spectrum, i.e. from 700 to 1500nm. The region from 750 to 1100 nm is of particular importance foroptical character recognition (OCR) and for energy conversion, e.g. fromlaser radiation to heat. Many OCR systems use solid state semi-conductorlasers, which generally emit at 780-830 nm, as the radiation source andphotodiode detectors based on silicon which have peak sensitivity around900 rim. The powerful YAG laser, which is widely-used for energyconversion, emits at 1060 nm. The compounds of Formula 1 in which n=0generally have fairly narrow absorption bands in the 750-850 nm regionwhile the compounds of Formula I in which n>0 have a broader absorptionband in the 800-950 nm region.

The compounds of Formula I in which n=0, m=15-16 and R--X-- is arylthio,especially 4-(C₁₋₄ -alkyl)phenylthio, exhibit an intense narrowabsorption curve with very high extinction coefficients (typically about10⁵)) centred around 750-800 nm and are compatible with the solid statelasers. There is little absorption in the visible region (400-700 nm) sothat the compounds are almost colourless, a very desirable property inapplications such as security printing.

Compounds of Formula I, in which n=4 and m=7 or 8, particularly those inwhich Y=S, Z=NH and R¹ is phen-1,2-ylene and R is arylthio exhibit amuch broader absorption band centred at 800-900 nm and lower extinctioncoefficients (typically about 3-5×10⁴). Such compounds are compatiblewith both semi-conductor lasers and silicon detectors and, to a lesserextent, with YAG lasers.

Sulphonation normally has little or no effect on the absorptionproperties of organic molecules. Therefore, it is surprising thatsulphonation of the compounds described in EP 155780A should producesignificant changes in their absorption spectra.

An unsulphonated analogue of Formula I (RX=4-methylphenylthio, m=15 or16, Pc=Cu(II)Pc, n=p=0) has a narrow band spectrum with a shoulder at ca685 nm. The sulphonated compound of Formula I (p=12.5, m=Na) has abroader band spectrum at the same position without the pronouncedshoulder at 685 nm.

An unsulphonated analogue of Formula I (RX=4-methylphenylthio, m=8, Y=S,R¹ =1,2-phenylene, Z=NH, n=4, p=0) has an absorption maximum at 890 nmin CH₃ Cl with a half-band width of 270 nm. The sulphonated compound ofFormula I (p=10, m=Na) has an absorption maximum at 833 nm in water anda half-band width of 360 nm. Thus, the sulphonated compound has anunexpectedly broader absorption band, making it more compatible withsemi-conductor lasers (sharp emission at 780-830 nm) and silicondetectors than the unsulphonated analogue.

Various applications of the present compounds, especially for printinginks, require products which are soluble in solvents of differingpolarities. The major requirements are for water-soluble products (waterand water-alcohol or water-glycol mixtures), alcohol (typicallymethanol, ethanol and propanol) and glycol (typically ethylene glycoland diethylene glycol) soluble products and ketone (typically MEK)soluble products. The sulphonated products and their alkali metal andammonium salts, especially those containing from 8 to 16 sulphonategroups, are highly soluble in water, water/glycol and water/alcoholmixtures. The fatty ammonium and diarylguanidinium salts of thesesulphonated products exhibit good solubility in polar organic media suchas lower alcohols, e.g. ethanol, and glycols, e.g diethylene glycol.

For inks based on solvents of lower polarity, such as ketones,hydrocarbons and chlorinated hydrocarbons, such as MEK, toluene anddichloromethane, unsulphonated versions of the compounds of Formula I,i.e. those in which p=0, are especially suitable and such compounds aredescribed in EP 155,780A and in our co-pending UK Application No.8705576.

Mixtures of compounds within the three classes can be employed toproduce intermediate effects in terms of absorption band-widths andsolubilities.

The high extinctions coefficients, particularly of the compounds inwhich n=0, allow the production of prints with very high print contrastratios (PCR), generally >60%, and in some cases >75%, for efficient andaccurate reading with OCR equipment.

Other applications include (i) ink drying where the improved absorptionof radiant energy, e.g from infra red lamps, and its conversion intoheat permits faster drying rates in printing applications, (ii)flash-fusion of toners in electro-reprography and (iii) as chargecontrol agents in electro-reprography.

The compounds of Formula I exhibit good durability, including highfastness to heat and light. The durability to light, in particular, inconsiderably greater than for other known classes of infra-red absorberssuch as cyanines, triphenylmethanes, complex nickel salts of dithiols,oxathiols and arylimminium and di-imminium compounds.

The present invention is further illustrated by the following examplesin which all parts and percentages are by weight unless otherwiseindicated.

EXAMPLE 1

(a) 2-Aminothiophenol (58.4 g, 0.42 mol), 4-methylphenylthiol (99.2 g,0.08 mol), and potassium hydroxide (105.6 g, 1.6 mol), were stirred inDMF (800 ml) at 120°-130° C., for 40 minutes. To the mixture was added,portionwise over 30 minutes, commercial bromotetradecachloro-CuPc(VYNAMON Green 2GFW, 113.9 g, 0.10 mol) and the mixture stirred at 125°C. for 2 hours. After cooling to 80° C. ethanol (1600 ml) was added tothe stirred reaction mass in order to precipitate the product. Theprecipitate was filtered off and washed with ethanol and water. Thepaste was suspended in water, stirred, filtered, and washed with waterand ethanol. The wet solid was dried in a vacuum oven at 40° C. and 20mbar.

    ______________________________________                                        Yield:      86          g (42% theory)                                        WL.sub.max :                                                                              890         nm (in CH.sub.3 Cl)                                   EC.sub.max :                                                                              46,000      (in MEK)                                              Solubility: 10%         (in MEK, 25° C.)                               ______________________________________                                         WL.sub.max is the wavelength of the absorption maximum; and                   EC.sub.max is the extinction coefficient at the absorption maximum.      

The product comprised a mixture of substituted-thio-CuPc with theaverage formula,hepta(4-methylphenylthio)-tetra(1-amino-2-thio-phen-1,2-ylene)-CuPc(OTCPC).

(b) Fuming sulphuric acid (sp.gr. 1.92, 520 ml) was added to water (20ml) with stirring. To this was added OTCPC (100 g), over 20 minutes withstirring, while the temperature was held at 10°-20° C. with an ice-bath.The mixture was stirred for 21/2 hours at room temperature, then pouredonto ice (1.51 ), and the solid separated by filtration. The solid wasdissolved in ethanol (11), and the solution neutralised with a 32%aqueous solution of sodium hydroxide. After cooling, the inorganic saltswere removed by filtration, and the filtrate evaporated to dryness. Thecrude product was purified by dialysis through Visking tubing. Analysisof the product showed that each molecule carried, on average, 10sulphonate groups.

    ______________________________________                                        Yield:     135         g                                                      WL.sub.max :                                                                             833         nm (in H.sub.2 O)                                      EC.sub.max :                                                                             30,000      (in H.sub.2 O, MW cs 3057)                             Solubility:                                                                              >10%        (in H.sub.2 O, 25° C.))                         ______________________________________                                    

EXAMPLE 2

The procedure of Example 1(b) was repeated except that the OTCPC wasreplaced by an equivalent quantity ofpentadeca(4-methylphenylthio)-CuPc. The product contained on average,12.5 sulphonate groups per molecule and had the following properties:

    ______________________________________                                        WL.sub.max :                                                                              765          nm (in H.sub.2 O)                                    EC.sub.max :                                                                              51,000       (in H.sub.2 O)                                       Solubility: >10%         (in H.sub.2 O, 25° C.)                        ______________________________________                                    

EXAMPLE 3

The procedure of Example 1(b) was repeated that the OTCPC was replacedby an equivalent quantity ofpenta(2-aminophenylthio)-penta-(1-amino-2-thiophen-1,2-ylene)-CuPc. Theproduct contained, on average, 9.5 sulphonate groups per molecule andhad the following properties:

    ______________________________________                                        WL.sub.max :                                                                             900       nm (broad peak, in H.sub.2 O)                            ______________________________________                                    

EXAMPLE 4

The product from Example 1b (15 g) was dissolved in water (150 ml)(Solution A).

1,1,3,3-Tetramethyl butylamine (13.6 g) was added to water (136 ml) anddissolved by the addition, with agitation, of 35% HCl, until theresultant solution was acid to Congo Red test papers (Solution B).

Solution B was added to Solution A, with good agitation, dropwise atroom temperature, whilst maintaining the pH at about 8 by thesimultaneous dropwise addition of 32% NaOH solution. After the addition,stirring was continued until precipitation of the product was complete.The product was recovered by filtration, and dried at 50° C.

    ______________________________________                                        Yield:     19        g                                                        Solubility:                                                                              >10%      (in ethanol, 25° C.))                             Solubility:                                                                              >10%      (in ethylene glycol, 25° C.)                      ______________________________________                                    

EXAMPLE 5

The product from Example 4, after optional purification to normalink-jet standards by known techniques e.g. dissolution in ethanol andfiltration to remove finely divided solid, was made up into an ink byaddition of known ink additives. The ink, after application to e.g.paper by known techniques gave prints which had a reflectance spectrumwith WL_(max) at 830 nm and a broad absorption which gave a good printcontrast ratio over the whole spectral range from 750-1000 nm.

EXAMPLE 6

The product from Example 2 (2.5 g) was stirred in solution at pH 10 and1,3-di-2-tolylguanidine (2.5 g) was added. The mixture was stirred atroom temperature and the pH adjusted to 5 with orthophosphoric acid.After stirring for 2 hours at room temperature at pH 5 the solid wasseparated by filtration and washed with a small volume of water. The wetsolid was dried in the electric over at 80° C.

    ______________________________________                                        Yield:      3.0        g                                                      WL.sub.max :                                                                              770        nm (in ethanol)                                        EC.sub.max :                                                                              91,000     (in ethanol)                                           Solubility: >10%       (in ethanol, 25° C.)                            ______________________________________                                    

EXAMPLE 7

The product from Example 1(b) (4.0 g) was dissolved in water (45 ml)(Solution A). 3,5,5-trimethylhexylamine (2.21 g) was added to Solution Aand after stirring for five minutes the pH was adjusted to 4.5 with 88%H₃ PO₄. The product was recovered by filtration and dried at 50° C. togive 4.5 g of product. The product has good solubility in ethanol anddiethylene glycol.

EXAMPLE 8

The product from Example 1(b) (15.2 g) was dissolved in water (150 ml)(Solution B).

2-Ethylhexylamine (6.6 g) was added to water (66 ml) and dissolved bythe addition, with agitation, of conc. hydrochloric acid, until theresultant solution was acid to Congo Red test papers. The solution wasdiluted to 100 ml by the addition of water (Solution C).

Solution C was added dropwise over 30 minutes to Solution A, underagitation, at ambient temperature, keeping the pH at 6-8 by thesimultaneous addition of 32% NaOH solution. After stirring for a furtherone hour, the precipitated product was filtered off, washed with alittle water and dried at 50° C. to give 18.3 g of product. The producthad good solubility in ethanol at 25° C.

EXAMPLE 9

A 6% ink was made up by mixing 3 parts of the product of Example 4 and 1part of the product of Example 6 in 62.6 parts of methanol. The ink,after application to paper by gravure, printin, gave a print with areflectance spectrum having broad absorption over the 700-1000 nm rangeand a good print contrast ratio over the same range.

EXAMPLE 10

The product of Example 1(b) (3.0 g) was dissolved in water (30 ml) atambient temperature (Solution A). Cetylpyridinium chloride (3.6 g) wasadded portionwise with stirring to Solution A. The precipitated solidwas filtered, washed with water and dried at 50° C. This product hasgood solubility in ethanol at 25° C.

EXAMPLE 11

The procedure of Example 10 was repeated except that the cetylpyridiniumchloride was replaced by an equivalent quantity ofcetyltrimethylammonium chloride. The resultant product has goodsolubility in ethanol at 25° C.

What is claimed is:
 1. A phthalocyanine compound of the formula:

    (R--X--).sub.m Pc(--Y--R.sup.1 --Z--).sub.n (--SO.sub.3 M).sub.p I

wherein Pc is a phthalocyanine nucleus (Pc); each R independently is amonovalent aromatic radical linked to a peripheral carbon atom of the Pcnucleus through X selected from phenyl, naphthyl, thienyl, furyl,pyrryl, thiazolyl, isothiazolyl, quinolyl, indolyl, pyridyl,benzoimidazolyl and benzothiazolyl each of which is unsubstituted orsubstituted by up to 3 substituents selected from C₁₋₂₀ -alkyl, C₁₋₂₀-alkoxy, S-C₁₋₂₀ -alkyl, halogen, aryl, S-aryl, nitro, cyano,di-N-alkylamino, N-alkyl-N-arylamino, di-N-arylamino, COOH, COT¹, CONT¹T², SO₂ T¹ and SO₂ NT¹ T² in which T¹ and T² are selected from H, alkyl,aryl and aralkyl; X selected from S, Se and Te; m is 4 to 16; each R¹independently is a divalent aromatic radical linked to two adjacentperipheral carbon atoms of the Pc nucleus through Y and Z selected fromphenylene, naphthylene, substituted phenylene and substitutednaphthylene in which the substituents are selected from C₁₋₂₀ -alkyl,C₁₋₂₀ -alkoxy, S-C₁₋₂₀ -alkyl, halogen, aryl, S-aryl, nitro, cyano,di-N-alkylamino, N-alkyl-N-arylamino, di-N-arylamino, COOH, COT¹, CONT¹T², SO₂ T¹ and SO₂ NT¹ T² in which T¹ and T² are selected from H, alkyl,aryl and aralkyl; Y is selected from S, NT, Se and Te; Z is selectedfrom S, Se, Te, NT and O; T is selected from H, alkyl and aryl; n is 0to .[.7.]. .Iadd.6.Iaddend.; .Iadd.2n+m is 13 to 16; .Iaddend. M isselected from H; a metal; ammonium; substituted ammonium of the formulaNQ₄ in which at least one Q is a C₆₋₂₀ -fatty aliphatic group or two Qstogether with the nitrogen atom, form a heteroalicyclic orheteroaromatic group selected from pyridino, piperidino and morpholinoand the other two or three Qs are each independently selected from H,C₁₋₄ -alkyl, phenyl and benzyl; and diarylguanidinium of the formula: T³--NH--C(NHT⁴)--NH--T³ in which each T³ is phenyl or C₁₋₄ -alkylphenyland T⁴ is H or C₁₋₄ -alkyl; and p is from 1 to
 16. 2. A compoundaccording to claim 1 in which Pc is Cu(II)Pc.
 3. A compound according toclaim 1 wherein Y is S, Se or Te.
 4. A compound according to claim 1wherein Q is selected from 3,5,5-trimethylhexyl, 2-ethylhexyl,1,1,3,3-tetramethylbutyl, 1,2,2-trimethylpropyl, 2-ethylbutyl,1-propylbutyl, 1,2-dimethylbutyl, 2-methylpentyl, 1-ethylpentyl,1,4-dimethylpentyl, 1-ethyl-3-methylpentyl, hexyl, 1-methylhexyl,3-methylhexyl, 1,3,3-trimethylbutyl, 1,5-dimethyl-hexyl, heptyl,1-methylheptyl, 1,4-dimethylheptyl, octyl, nonyl, 1-methylnonyl, decyl,dodecyl, tridecyl, pentadecyl, hexadecyl and octadecyl.
 5. A compoundaccording to claim 1 wherein one Q is C₈₋₉ -alkyl and the other three Qsare H.
 6. A compound according to claim 1 whereinPc is Cu(II)Pc; R isphenyl, C₁₋₄ -alkylphenyl or C₁₋₄ -alkoxyphenyl; X is S; m is 8 to 16;R¹ is phen-1,2-ylene, naphth-1,2-ylene or naphth-2,3-ylene; Y is S; n is0 to 4; Z is NT, S or O T is H or C₁₋₄ -alkyl; M is selected from H,alkali metal, NH₄, NH₃ Q and diarylguanidinium; and Q is a C₈₋₉ -alkyl.